Automatic cut-out for electric flatirons



Sept. 3o, 1924.

F. THORNTON, JR

AUTOMATIC CUT- OUT FOR ELECTRIC FLATIRONS Filed NOV. 29. 1921 INVENTORFran/r 7720//770/2,

WITNESSESI cdnzg.

ATTORNEY Patented Sept. 30, 1924.

UNITED STATES PATENT OFFICE.

FRANK THORNTON, JBL, OF MANSFIELD, OHIO, ASSIGNOR TO WESTINGHOUSE ELEC-TRIO PRODUCTS COMPANY, A CORPORATION 0F MICHIGAN. i

AUTOMATIC CUT-OUT FOR ELECTRIC FLATIRONS.

Application -filed. November 29, 1921. Serial No. 518,545.

T0 all whom it may concern.'

Be it known that I, FRANK THORNTON, Jr., a citizen of the United States,and a resident of Mansfield, in the county of Richland and State ofOhio, have invented a new and useful Improvement in Automatic Cut- Outsfor Electric Flatirons, of which the following is a specification. l

My invention relates to electrically heated apparatus and particularlyto means for limiting the temperature of electrically heated flat irons,and it has for its object to provide a combined terminal block,temperature indicating, temperature limiting and circuitinterruptingdevice for such application.

It is highly desirable to limit the temperature which may be reached bythe body of an electrically heated flat iron and to permanentlyinterrupt the circuit in case the temperature of the working surfacereaches a predetermined value. It has not been found practicableheretofore to use a bimetallic strip to effect the interruption of thecircuit, as the maximum permissible temperature of the iron is so highas to injuriously affect the metal employed in the strip, and thesettlng thereof is changed. Expansion members have also been suggestedto eect the interruption of the circuit, but, so far as I am aware, noneof these devices have proved effective in actual commercial work.

- In practising my invention, I provide an insulating casing secured tothe handle strap at the rear of the iron containing a knifeblade switchwhich 1s spring-biased .to its open position. The switch blade ispivotally mounted on one of the bolts securing the casing to the handlestrap, a ratchet being also mounted on said .bolt and being normallysecured thereto by a solder joint. A pawl on the knife blade co-operateswith the ratchet to hold the switch in its closed position when it hasbeen manually moved thereto. A second bladeis pivotally mounted on thefirst one, a spring being provided to yieldingly maintain it in properoperative position relatively to the first blade, said.

spring serving also toyieldingly maintain the paWl in its operativeengagement wlth said ratchet.

A spring-biased stop member 1s so located in the casing as tomomentarily arrest the movement ,of K'the -second knife blade While theswitch is being manually closed, so as plate,

to result in a quick make action, the stop permitting, however, a quickbreaking action when the solder holding the ratchet softens and thespring connected to the knife blade disengages it from the stationaryjaws.

In the single sheet of drawings,

Figure 1 is a view, in side elevation, of an electric flat ironcomprising the device embodying my invention, portions being brokenaway.

Fig. 2 is a view, in front elevation, of the combined terminal block andcircuit-interrupting device, the outer cover portion of the casing beingremoved;

Fig. 3 is a longitudinal section thereof taken on the line III- III ofFig. 2;

l Fig. 4 is a partial cross sectional view on the line IV--IV of Fig. 3,and Fig. 5 is a lateral cross 'sectional view taken onthe line V-V ofFig. 3.

An electrically heated iron comprises a bottom plate 10, a heatingelement 11 and cured together by means of a plurality o'f screws 13,only one of which is illustrated in Fig. 1 of the drawing. A covermember 14 is secured, in its proper operative position, on the bottomplate by means of a suitable bolt 15. A handle 16 is mounted on thecover member by means of suitable handle straps 17 and 18, the lowerends of the handle straps being secured against the cover member bymeans of rivets 19. The bottom the heating element and the top plateconstitute what may be termed the body portion of the iron.

The heating element 11 may be of any desired type or constructionusually employed in the art and is not, therefore, described in detail.It may beprovided with a plurality of terminal members 21 to which theends of the resistor may be suitably secured, as by means of screws 22and nuts 23.

A terminal casing'24 comprises an inner part 25 and an outer part 26,each being made of any suitable insulating material and so formed as tointerfit and constitute a substantially closed .casing having a chambertherein.

vA metallic strap member 27 extends longitudinally of thev casing at oneside thereof provided, at its lower end, with a clamping screw 28, whichnot only secures the end of insulating member 25 but alsocl'ampsfthereon a conductor 29 extending from one of the terminalmembers 21. A similar clamping screw 31 is provided' at the upper end ofthe member 27 and serves to suitablyclamp a conductor 32 of a twinconductor cable 33 against the strap 27 yas well as to secure the upperend of the strap against the casing part 25. At the opposite side of thecasing is provided va relatively short metallic strap 34 to the upperend `of which is secured the other conductor 35 ofthe supply cable 33 bymeans of a clamping screw 36. 4At the.n

lower end of the member 34 is secured a twopart metallic switch jaw 37,being secured against the strap 34 and mounted in its pro-per operativeposition in thev casing, by means of a screw 38, this construction beingillustrated in Fig. 4 of the drawing. A metallic strap member 39'is'located belowthel strap 34, extending substantially longitudinallyof the member 25, a suitable clamping screw 41 being provided at theupper end to secure thereagainst a substantially similar two-part switchjaw 37. A clamping screw 42, located at the lower end of the member 39,serves to secure thereto a conductor 43,

, the lower end of which is connected to the other one of the terminals21 of the heating element 11. f

A lever arm 44 of a two-part knife-blade switch is pivotally mounted ona bolt 45 is secured against the handle strap by means of nuts 46 and47. A ratchet wheel 48 is located in the lower end of the casing which jnorm-ally secured to the body of the bolt 45 by means of a solder joint49, a washer 51 protecting the insulating )material of the 'casing 25from the solder which, as will be hereinafter set forth more in vdetail,softens when the temperature of the body portion of the iron reaches apredetermined temperature. Y Y

The arm 44 has secured thereto, vintermediate its ends, a spring member52, Athe outer end of which may be mounted in a side wall of the casing.An integral lateral extension 53, substantially of arcuate form, isprovided adjacent the upper end of the lever arm 44, an insulatingmember 54 being.

suitably secured thereto at the outer end thereof to extend outwardlythrough an opening 55 in the side wall of the casing member 25 to permitof manually moving the switch to its closed position.

A switch 56 is pivotally mounted on the lever arm 44 intermediate itsends, the intermediate portion ofthe switch blade 56 being so bent as tobe a substantial .distance away from, and parallel to, the lever arm 44,the construction being more particularly illustrated in Figs. 3 and 4 ofthe drawing. Av spring member 57 mounted upon a pivot pin 58, upon whichone end of the switch blade 56 is also mounted, serves to resilientlypress the switch blade against a stop meinber 59 integral with the leverarm 44 adjacent its upper end.

The other end of the spring member 5T serves to yieldingly press a pawl61 into operative engagement with the teeth of the ratchet member 48,the construction being such that, while the lever 44 and the switchblade 56 mounted thereon are moved b v means of the member- 54, the pawllmoves over the ratchet 48 and prevents the return 'of the knife Switchunder the influence of 'the spring 52 until a ature of the body reached,detail.

ln order to obtain a quick make action ll provide a stop member 62pivotally located in the path of travel of the knife blade 56, a pin 63being located in the casing member 25 to limit the position of the stop62 which is pressed against the pin 63 'by means of a spring 64. lVhenthe knife switch is moved by the operator in a counterclockwisedirection in the mechanism illustrated, part-icularly in Fig. 2 of thedrawing, the switch blade 56 is momentarily arrested in its movement bythe stop member 62 until the lever arm 44 has been movedto substantiallythe position illustrated by the full lines in Fig. 2, when the upper endof the blade 56 is released and moves quickly into its positionillustrated in the full lines of Fig. 2 `under the influence of the coilspring 57,.`

So long as the operator is using the iron in ordlnary ironing operationsthe temperature of the body portion ofthe iron will not reach anexcessively high value but if the Operator Should leave the iron for anextended length of time the temperature of not only the bottom plate 10but also of the top plate`l2aand 0f the cover member 14 would reach adngerously high value. This heat is conducted by the terminal strap 18to the bolt 45 and to the solder joint 49 and, after a predeterminedlength of time, the solder joint softens and permits the spring 52 tomove the lever arm 44 and the switch blade 56 quickly to the openposition, substantially as illustrated by the broken lines of Fig. 2.The stop member 62 does not interfere with the return movement of theknife blade 56. lt is impossible for the operator to immediately reclosethe circuit and lhave the mechanism maintainit in its closed position asthe temperature of the entire iron and, of course, particularly of thesolder joint must fall before the ratchet 48 is again secured. to thelever arm 44. When this occurs, the operator may again move the switchto its closed position by means of the member 54, in the mannerhereinbefore described and the switch then remains in its closedposition until the recurrence of the dangerously high temperature.

portion of the iron is predetermined temperllO The member 54 serves alsoto indicate whether the switch is in its open or its closed position andhence whether or not current is traversing the heating element. if thesupply circuit conductor is connected to a suitable source of energy.

A second bolt 65 and nut 66 may be employed to secure the upper end ofthe casing against the handle strap 18, and a plurality of bolts 67 andnuts 68 may be employed to secure the outer casing 26 against the innercasing 25, suitable openings 69 being provided in the casing 25.

The device embodying my invention thus provides a normally non-removableterminal casing and temperature-indicating, temperature-limiting,circuit-interrupting and current-indicating means for an electricallyheated flat iron, which device is operative to automatically interruptthe circuit upon the occurrence of a predetermined temperature in thebody of the iron.

lVliile I have illustrated a particular embodiment of the deviceeffective to operate as hereinbefore described, I do not wish to belimited thereto, as many modifications may be made without departingfrom the spirit and scope ofA my invention and I desire, therefore, thatonly such limitations shall be placed thereon as are imposed by theprior art or are specifically set forth in the appended claims.

I claim as my invention 1. A combined terminal and temperaturelimitingdevice for an electrically heated iat iron comprising a handle member,and a cover member to which said handle member is secured, said devicecomprising an in sulating casing, a bolt for securing said .casing tosaid handle member, a switch in sald casing biased to its open position,means for manually closing said switch, locking means for holding saidswitch in its closed position, means for securing said locking means tosaid bolt, said lockin and securing means permitting said switc i' toopen at a predetermined temperature of said iron.

2. A combined terminal and temperaturelimiting device for anelectrically heated lat iron comprising a handle member, and acovermember to which said handle member is secured, said devicecomprising an insulating casing, a bolt for securing said casing tosaid. handle member, a switch member having a turning movement on saidbolt, means for biasing said switch member to its open position, meansoperatively associated withsaid bolt to hold said switch member in Y itsclosed position, and means for securing said switch-holding'means tosaid bolt, said switch and switch-holding means having a turningmovement on said bolt at a predetermined temperature of said iron.

A combined terminal, temperatureliiniting'aiid circuit-interruptingdevice for anelectrically heated flat iron comprising an insulatingcasing, a bolt for holding said casing against saidflat iron, a leverpivotally mounted on said bolt, a switch blade pivotally mounted on saidlever, means for resiliently maintaining said switch blade normally in apredetermined position relatively1 to said lever, manually operablemeans for causing said lever to have a turning movement on said bolt,means temporarily arresting the movement of the outer end of said switch.blade during the movement of said lever, and means operativelyassociated with said bolt for locking said lever and switch blade in apredetermined position.

4. A terminal and temperature-limiting device for an electrically heatediiat iron comprising a cover member, and a handle member securedthereto, said device comprising an insulating casing, a bolt forsecuring said casing against said handle member, a manually closableswitch member in said casing, resilient means tending to open saidswitch, and means for locking said switch member in its closed position,said locking means being operatively associated with said bolt andhaving a turning movement thereon to permit the resilient means to opensaid switch at a predetermined temperature of said iat iron.

In testimony whereof, I have hereunto subscribed my name this nineteenthday of November 1921.

FRANK THORNTON, JR.

